Stabilized hydrocarbon fuel oil composition



,4 STABIIJIZIEDHYDROCARBON FUEL OIL COMPOSITION Joel R. Siege],Irvington, N.J., assignor to Esso Research and Engineering Company, acorporation of Delaware No Drawing. Filed Oct. 15, 1957, Ser. No.690,184

Claims. (Cl. 44-62) The present invention is directed to thestabilization of hydrocarbon oils, and particularly of petroleum middledistillates, against discoloration and the formation of sediment duringstorage. More particularly, the invention concerns the stabilization ofhydrocarbon fuel oils during storage by incorporating into those oilsaddition agents that inhibit degradation of the fuel oils and which atthe same time serve to disperse any sediment-producing materials thatmay have formed in the fuel oil. The addition agents of this inventionare of particular value because they do not form ash or residues whenthe fuel oils are burned.

The hydrocarbon fuel oils with which this invention is particularlyconcerned broadly comprise petroleum distillates that are commonlyemployed in various burner systems, as fuels for diesel engines, as jetfuels and as domestic or industrial heating oils. Such fuel oils may begene'ra'lly characterized as those that consist of a major proportion ofhydrocarbons boiling'in the range of from about 350 F. to about 900 F.Fuel oils tend to deteriorate on storage, particularly'when they containcracked hydrocarbon stocks, as they now commonly do. It has been foundthat if percent or more of the fuel oil composition comprises crackedstocks, the formation of sludge or sediment during storage may bemarkedly increased, leadingto the plugging or fouling of oil lines,filters and burner nozzles.

Attempts have been made in the past to overcome the sediment-formingproblem by incorporating addition agents in the fuel oils. Many of theseadditives, however, particularly metal salts such as metal naphthenates,metal sulfonates and metal salts of alkyl phenol sulfides, have beenobjectionable in that they leave an ash residue on combustion.

' It is a primary object of this invention to improve the stability ofpetroleum hydrocarbon fuel oils against the formation and precipitationof sediment while at the same time minimizing the formation of ash whensuch fuels are burned. It is an additional object of the invention toimprove the color stability of such fuel oils.

. It is still a further object of this invention to provide improvedaddition agents, and improved methods of preparation of the same, foraccomplishing the objects stated above.

. In accordance with the present invention, the sedimentformingtendencies of petroleum hydrocarbon oils, and particularly of fuel oils,can be markedly reduced by incorporating therein minor proportions, ofthe order of from about 0.001%to' about 0.2%, of a polymeric materialcontaining an amidine group. The polymeric materials of this inventionare preferably prepared by co- 'polymerizinga mixture of three types ofmonomeric materials, namely, a long chainalcohol ester of a conjugatedunsaturated dibasic acid, a vinyl ester of a short chain fatty acid andan N-vinyl amide, and then reacting the resulting copolymer with aprimary amine, preferably a tertiary alkyl primary amine. Suitable vinylesters include vinyl acetate and vinyl propionate. The dibaic mat-ovinyl ester.

"ice

acid ester may be a maleate, fumarate, itaconate, aconitate, or thelike. 7 p

The dibasic acid ester component of the copolymer is preferably an esterof fumaric acid or of mixed fumaric and maleic acids and a long chainalcohol of from about 8 to 24 carbon atoms such as octyl (C laury1 (Ctridecyl (C arachidyl (C behenyl (C or tallow (C alcohols produced bythe hydrogenation of tallow acids. J

The N-vinyl amide component of the copolymer is characterized by thegeneral structures:

and

H?==CH where, in the first formula, R is selected from the groupconsisting of hydrogen and alkyl groups of 1 to. 18 carbon atoms and Ris'an alkyl group of from 1 to 18 carbon atoms, and, in the secondformula, 11 is an integer from 2 to 4. Preferably R and R are alkylgroups of 1 to 8 carbon atoms. a The second formula given aboverepresents compounds of the first formula wherein R and R have beenreplaced by a single divalent hydrocarbon radical of from 2 to 5 carbonatoms to give an internal or cyclic amide. e

Among the N-vinyl. amides that may be employed in practicing thisinvention are included N-vinyl-N-methyl acetamide, N-vinyl oleamide,N-vinyl pyrrolidone, N- vinyl-N-isopropyl-Z-ethyl hexoic amide, N-vinylpiperidone, -N-vinyl-fi-methyl pyrrolidone, and 'N-vinyl-evalerolactam;i

Preferably the copolymers are prepared from mixtures of the monomers inthe proportion of about 1 to 1.5 moles of vinyl ester, about 0.5 to'0.7mole of dibasic acid ester and about 0.5 to 0.3 mole of the N-vinylamide. Preferably the amounts of the latter two components should add upto about 1 mole for the l to 1.5 moles of The'polymerization isconducted in a solution of benzene or other solvent, e.g., xylene,toluene, etc. (50 percent by weight) at temperatures of 60 to 212 F. andmay be promoted by gamma radiation or by use of a peroxide type catalystsuch as benzoyl peroxide, a hydroperoxide or an azo catalyst suchasalpha-alphaiazo-bis-iso-butyronitrile. 'The polymerization is corn,ducted until a product of -0 to 100,000 but preferably 2000 to 20,000Staudinger molecular-weight is produced. The copolymer product afterboiling off the solvent is then reacted with a tertiary alkyl primaryamine. The amines employed in this invention are preferably those havingfrom about 4 to about 20 carbon atoms. Among the amines that may be usedare tertiary octyl primary amine, tertiary dodecyl primary amine, and acommercial mixture of tertiary alkyl primary amines of 12 to 15 carbonatoms, marketed under the name Primene 81R.

The copolymer product is reacted with the amine by mixing the productwithfrom 1 to 3 moles, preferably 1.25-2.5 moles, of amine per mole ofamide group in the copolymer, the mixture being dissolved insomesuitable non aqueous solvent boilin'g'in the range of about 212 F.toabout 350 F., e.g. toluene, xylene. The mix is then refluxed at atemperature of 212-350" F., preferably 230300 F., for a period of 110hours, preferably 2-6 hours, in a nitrogen atmosphere in the presence ofa dehydrating agent such as 110% (based on the polymet) of fused zincchloride or aluminum chloride for example. Alternatively, or inconjunction with the dehydrating agent, the refluxing can be conductedin an apparatus provided with a water separator. The product isfiltered, the solvent and; excess amine are-removed-by evaporation in avacuum and the polymer isaredissolved in the desired solvent. In the;reaction, the; amine group reacts with the amidegroup of the polymer,forming water. and an azomethine group C=NR. The water is removed bydistillation orby; absorption: by the de hydrating agent.

The following, examples will serve to'illustrate: this invention.

EXAMPLE: 1

Vinyl acetate, tallow fumarate and N-vinyl pyrrol idone in the moleratio of 1-.4/.635/ .365 were dissolved in sufiicient benzene to make a50 percent solution by weight. 1.0 percent of benzoyl peroxide was addedand polymerization was conducted at 110 F. for 20 hours in the presenceof gamma radiation at a dose rate of 1 mr./hr. Then 0.7 mole of tertiaryoctyl amine (which was an excess) was added along with a quantity ofxylene equal in weight to the? polymer mix. The blend was refluxed for4.5 hours in a nitrogen atmosphere in the presence of 8.8 percentanhydrous zinc chloride, based on the polymer. This solution was thenfiltered, the solvent and excess amine were removed under reducedpressure, and the polymer was dissolved in 50'per cent of. its weight ofbenzene. It was established'byinfrared spectroscope thatthe amidinegroupingwas'present in the polymer.

EXAMPLE 2 a A commercial fuel oil was selected for stability tests usingthe oil itself as well as a blend of the oil containing the additivedescribed in the foregoing example. The oil was a blend of 50 percentvirgin distillateand 50 percent cracked stock. Typical inspections forthis type of oil are as follows:

The base fuel and the additive-blend were subjected to a stability testwhich consisted in storing thefuel oil for a period of 16 hours whilemaintaining the temperature at 210 F. At the end of the 1.6 hours thefuel oil was filtered and the amount of sediment that had been formedduring the storage period was quantitatively determined.

Table I sets forth the data obtained in these tests:

Table l AOOELERA'IED STORAGE STABILITY TEST Insoluble Sediment FormedAfter 16 Hours 210 F., tug/600 g. Oil

Additive 1 None. "0.01% of Product of Example 1 It will be noted fromthe data in Table 1 that the 1 polymer was very effective in reducingthe sedimentforming tendency of the fuel oil.

It is not intended that this invention be limited to the specificexamples presented by way of illustration. The scope of the invention islimited only by the appended claims.

What is claimed is:

1. A stabilized hydrocarbon fuel oil composition consisting of a majorproportion of hydrocarbons boiling in the range of from about 350 F. toabout 900 F., and a minor proportion of a reaction product of atertiaryalkyl primary amine with a copolymer of a vinyl'ester of a shortchain fatty acid, a long chain alcohol'ester of a conjugated unsaturateddibasic acid, and an N-vinyl amide selected from the structural formulasconsisting of:

wherein R is selected from the group consisting of hydrogen and alkylgroups of 1 to 18 carbon atoms and R is an alkyl group of from-1 to 18carbon atoms, and wherein n is an integer from 2 to 4, wherein theamount of vinyl ester utilized is in the range from about 1 to 1.5moles, wherein the amount of dibasic acid present is in the range fromabout 0.5 to 0.7 mole and wherein the amount of N-vinyl amide is presentin a concentration from about 0.5 to 0.3 mole, said reaction productbeing present in said hydrocarbon oil composition in an amountsuflicient to inhibit the formation of sediment in the said oil.

2. The composition as defined by claim 1 wherein the concentration ofthe reaction product in the hydrocarbon oil composition is within therange of about 0.001% and about 0.2%.

3. The composition as defined by claim 1 wherein the amine has from 4 toabout 20 carbon atoms.

4. The composition as defined by claim 1 wherein the reaction product isobtained from the reaction. of from 1 to 3 moles of amine per mole ofamido group in the copolymer.

5. The composition as defined by claim 1 wherein said reaction productis prepared from tertiary octyl amine and a copolymer of vinyl acetate,tallow. furnarate and N-vinyl pyrrolidone.

References Cited in the file of this patent UNITED STATES PATENTS-2,387,501 Dietrich Oct. 23, 1945 2,469,737 McNab et al May 10, 19492,553,325 Loritisch May 15, 1951 2,597,202 Lawney May 20, 1952 2,626,945Carlin Jan. 27, 1953 2,737,452 Catlin et a1 Mar. 6, 1956 2,771,348Meguerian Nov. 20, 1956 2,793,943 Moore May, 18', 1957 2,800,401Lusebrink et al July 23, 1957 2,800,452 Bondi et a1. July 23, 1957FOREIGN PATENTS 523,748 Belgium Nov. 14', 1953

